In December 2005, IACS—the International Association of Classification Societies— adopted the Common Structural Rules for Bulk Carriers （CSR-BC） and Common Structural Rules for Double Hull Oil Tankers（CSR-OT）. All IACS member classification societies were required to enforce the CSR-BC and CSR-OT requirements after they officially went into effect on 1 April 2006.

The requirements of the CSR-BC apply to bulk carriers of 90 m of more in length and the requirement of the CSR-OT apply to double hull oil tankers of 150 m or more in length whose contracts for construction are dated on or after 1 April 2006. However, due to entry into force of the Common Structural Rules for Bulk Carriers and Oil Tankers (CSR BC & OT) on 1 July 2015, the CSR BC & OT applies to bulk carriers of 90 m of more in length and double hull oil tankers of 150 m or more in length whose contracts for construction are dated on or after 1 July 2015.